What makes you believe that he has had too much D3? How often do you give your cham the D3 supplement? What brand are you using? Different brands have different amounts of D3, so the more info you provide us, the better we can help. Like Linda said above, a 100W basking bulb is probably overkill, but it will come down to your ambient temperatures and how far away the bulb is from the basking site. Also, what type of heat bulb are you using (e.g. halogen, incandescent, LED). Nowadays, you have to be careful when buying incandescent bulbs because everything is phasing towards LED. Manufacturers are producing incandescent-looking bulbs that are in the 60-100 Watt range in light output but are actually equivalent to a 15W LED. Your bulb may say 100W (and then in small text underneath it will say "equivalent" and then state it's actually a 15W LED). If you live anywhere in California, it's nearly impossible to find an incandescent bulb in a hardware store. If you can tell me the brand (or better yet, have the box the bulb came in), we can help determine if your bulb is adequate for you jackson's chameleon.
Do you see your jackson's chameleon basking under the basking bulb? The D3 synthesis process requires heat, so if anything is wrong with the bulb, this could be an issue.
You say the urates are yellow. How do his eyes look? Do they look nice and round or are they sunk in? Hydration is going to be determined by your humidity/misting schedule, so be sure to fill out the form posted above by
@Beman.
